The present invention relates to a bicycle bottom bracket assembly and a roller bearing is connected to an end of the axle and the chainwheel is connected to the end of the axle.
A conventional bicycle bottom bracket 40 is shown in FIG. 4 and generally includes an outer tube 50 connected to the bicycle frame and an inner tube 42 is received in the outer tube 50 with an axle 41 extending through the inner tube 42. Two bearings 43 are respectively mounted to two ends of the axle 41 and two crank arms (not shown) are respectively connected to the two ends of the axle 41. Two ball securing rings 44 are respectively mounted to the two ends of the axle 41 and connected to two ends of the outer tube 50 to position the axle 41. The assembly for the bottom bracket is used for a long time. However, it is difficult to assemble the two ball bearings 43 in balance and precise. A chainwheel (not shown) is connected to one end of the axle 41 so as to be engaged with a chain which is connected to the other chainwheel co-rotatably mounted to rear wheel axle. The ball bearings 43 provide only point contact with the inner tube 42 and the axle 41 so that the rider rotates the crank arms, the ball bearing 43 on the end where the chainwheel is mounted is applied a larger force which could loosen the bearing 43 and affect the smoothness of the rotation of the axle 41.
The present invention intends to provide a bottom bracket assembly that uses a roller bearing on the end where the chainwheel is mounted and the inner tube has a flange to initially position the ball bearing on the other end of the axle.
In accordance with one aspect of the present invention, there is provided a bicycle bottom bracket assembly and comprising an outer tube connected to a bicycle frame and a first inner threaded section and a second inner threaded section are respectively defined in an inner periphery of two ends of the outer tube. An inner tube is received in the outer tube and a first end of the inner tube has a first outer threaded section so as to be engaged with the first inner threaded sections. A flange extends from a second end of the inner tube and a ball bearing is mounted to the flange. A roller bearing with a ring mounted thereto and the ring is engaged with an inner periphery of the first end of the inner tube. A positioning ring has a second outer threaded section which is engaged with the second inner threaded section of the outer tube. An axle extends through the roller bearing and the ball bearing.
The primary object of the present invention is to provide a bicycle bottom bracket assembly wherein the inner tube has a flange which initially position the ball bearing and makes the assembly simplified.
The other object of the present invention is to provide a bicycle bottom bracket assembly wherein a roller bearing is mounted to an end of the axle and a chainwheel is mounted to the end of the axle.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.